It is well known to use pumps for dispensing of adhesives, encapsulates, pastes and other high through low viscosity liquids and pastes. Recent developments in the processing of semiconductors include the introduction of packaging techniques which require high speed precision dispensing of epoxies, solder pastes encapsulates and underfill materials. In the past, augering screw type pumps like those disclosed in U.S. Pat. Nos. 5,819,983 and 5,795,390 have been employed in such applications; however with the advent of higher precision dispensing requirements, these pumps have reached their limit in terms of performance and accuracy. In order to overcome accuracy limitations of augering screw type pumps, a series of piston based positive displacement pumps like those manufactured by Asymtek, a Nordson Company have evolved. While exceeding accuracy of augering screw type pumps, these piston based pumps have suffered limitations in terms of the ability to service and clean parts of the pump exposed to the various fluids.
The apparatus of the present invention relates generally to positive displacement pumps. The invention further relates to positive displacement pumps for dispensing of adhesives, encapsulates, pastes and other high through low viscosity liquids and pastes.
One object of the present invention is to provide a precision dispensing pump for high accuracy dispensing of liquids such as adhesives, encapsulates, pastes and other high through low viscosity liquids and pastes.
Another object of the present invention is to provide a positive displacement pump for high accuracy dispensing of liquids such as adhesives, encapsulates, pastes and other high through low viscosity liquids and pastes.
Another object of the present invention is to provide a precision dispensing pump which has simplified cleaning of parts exposed to dispensing fluids in order to minimize down time for service.
Another object of the present invention is to provide a precision dispensing pump which has disposable parts exposed to dispensing fluids in order to minimize down time for service.
Another object of the present invention is to provide a precision dispensing pump which has repeatable calibration.